Electron discharge device



J. L. H. J,ONKER ETAL H 2,229,752

ELECTRON mscamcm DEVICE Filed July so, less 2 Sheets-Sheet 1 V ourpurmanna INVENTORS JOHAN L. H. JGNKERAND ADRIMIJJWM MNOVERBEEK 4 IATTORNEYS.

v m Pur 1941- J. L. H. JONKER ETAL 3,229,752

ELECTRON DISCHARGE DEVICE Filed July so, 1938 2 Shets-Sheet 2 -a|aIIIIIIIIIIIIIIII OUTPUT aur ur ourpw' IN V EN TORS- JOHAN A TTORNEYS.

Patented Jan. 28, 1941 PATENT OFFICE ELECTRON DISCHARGE DEVICE JohanLodewijk Hendrik Jonker and Adrianus vJ. W. M. van Overbeek, Eindhoven,Netherlands, assignors, -by mesne assignments to Radio Corporation ofAmerica, New York, N. Y., a corporation of Delaware Application July 30,1938, Serial'No. 222,174 In Germany August 3, 1937 4 Claims.

This invention relates to an'electron discharge tube wherein theelectrons are united to form two or more beams which intersect eachother. In the use of such tubes, which have been suggested and in whichthe electron beams intersect each other, a certain interference of thesebeams may occur in the discharge space.

The object of our invention is to provide such a tube in which one beamis accurately controlled by the space charge of another beam withoutundesirable interference of the beams.

In accordance with our invention an electron discharge tube in which theelectrons are united to form two or more beams which intersect eachother is provided with a grid-shaped electrode having a positivepotential and positioned between at least one of the cathodes and apoint of intersection of the beams, the various electrodes in the tubereceiving such voltages that a virtual cathode appears at or in theimmediate vicinity of the point or' points of intersection of theelectron beams.

We have foundthat. although the use of a tube having a plurality ofelectron beams intersecting each other, without additional means,involves a certain interference, suitable control of one of the beams bymeans of the space charge of another beam is possible only when care istaken to cause a dense space charge or virtual cathode to appear atabout the point of intersection of the beams. In this way the beams maybe so adjusted with respect to each other that a characteristic curvehaving the desired form can be obtained. An important field ofapplication of the present invention is to mixing tubes particularlywhere one beamjis controlled by an oscillator frequency and another beamby the incoming frequency. Another field is inobtaining a very strongamplification by using several systems one behind the other, as will beset forth hereinafter with regard to the drawings.

In order to obtain a suflicient space charge at the point ofintersection of the electron beam at least one grid having a positivepotential is, according to the invention, provided between the cathodeor cathodes and this point of intersection, and it has been found to beadvantageous for the distribution of field that there be no insulatingmembers such as the glass wall of the tube or the like in the vicinityof the point of intersection of the electron beams.

Although it is very simple and easyto use a separate cathode for eachelectron beam, and these separate cathodes may, if desired, havedifferent potentials, a common cathode may also be used for two or moreelectron beams, with which cathode the stream of electrons is divided bysplitting up and deflection into a plurality of beams to be controlledseparately. It is also possible to use either a. separate anode for eachsystem of beams or a common anode for all-of the systems.

The invention will be more clearly understood by reference to theaccompanying drawings representing diagrammatically and by way of ex- 10ample, several embodiments thereof.

In the accompanying drawings Figure 1 shows in section a deflection typetube; Figure 2 is a curve showing potential variation along the planeindicated by the section line; Figures 3 and 4 are modified forms ofdeflection tubes; Figure 5 is another form of tube in which one beamcon: trols a second beam; and Figure 6 is a sectional view of adeflection type tube with two beams from one cathode. 0

Figure 1 shows a deflectionv type beam tube in which I and 2 are outputanodes side by side which are in the path of and may be struck by astream of electrons 4 issuing from a main cathode 5 in the form of aconcentrated main beam. The electron beam 4 is deflected and controlledby another electron beam I issuing from another or auxiliary cathode 6.The electrons from both cathodes pass through a, tubular or cage-likegrid electrode 3 having a positive potential and constituting anauxiliary anode to which the discharge from the auxiliary cathode 6flows, and the two beams intersect and influence each other in the spaceinside this grid electrode. Beam forming electrodes 8 having a lowpotential may be mounted behind and partially surround the cathodes 5and B to concentrate the electron discharges into beams. Figure 2 shows,by the curve 9 the variation of space potential along theplane orsection 2-2 of the tube shown in Figure 1. When an electronic stream orbeam I is directed from cathode 6' into the space inside the gridelectrode 3 the potential along the plane 2--2 may vary according to thecurve I0, so that the electrons deviate and impinge on the anode 2, asdiagrammatically represented in Figure 1 by the beam I I. In this waydeflection through a. separate stream or beam of electrons is obtained.

Other control methods for influencing of the path so as to vary thedistribution of current maybe used, as shown, for example in Figure 3,in which the controlled or main stream or beam I5 of electrons isfocused on a main'output anode I2 by means of an electron optical systemconsisting of a negative electrode l8, a positive electrode I 6, anauxiliary anode consisting of two spaced members or concentratingelectrodes l3 and I! one of which, such as I3, is grid-like, and theother is a sheet-like member, both electrodes being maintained positivewith reference to the auxiliary cathode l 9. When an electronic stream Mfrom the cathode l9, concentrated into a beam forming electrode w behindthe cathode, is directed through the grid electrode 13 into the spacebetween l3 and I7 the electron optical system is disturbed, the mainbeam l5'is defiected and the greatest part of the controlled electronicstream passes to the auxiliary output anodes or electrodes 29 and El.mounted on pposite sides of the main output anode l2.

Amplification can be obtained by repeating several times the actionillustrated in Figure 3 since, by a suitable choice of the shape anddimensions of the electrodes and of the potentials applied, theelectronic stream l4 may be much weaker than the current which, as aresult of its infiuence, reaches the auxiliary output anodes 2E] and 2!.As illustrated in Figure 4, the current which passes the main anode 12through grid-like auxiliary anodes 2i] and 2| modifies the effect of theelectron optical system which controls a third main beam 22, so that avery small primary control current I l is suflicient for controlling alarge tertiary current. In the tube shown in Figure 4; the partscorresponding to those shown in Figure 3 are denoted by the samereferences. The tertiary electronic current 22 may strike a main anode23, and auxiliary output anodes 2B and 25, and is further infiuenced bythe sheet electrode 23 and the diaphragm El, both of which are atpositive potential with reference to the cathodes. The cathode systemconsists of a cathode 28 surrounded by a beam forming electrode 23. Ofcourse, the number' of these units may be chosen at will so that verystrong amplification is possible.

The amplification may be obtained by a modification of the electronoptical system, as in Figure 3; by deflection, according to'Figure 1, orby completely reversing or returning the electronic stream by the actionof the space charge. Figure shows a modification in which the operation,as appears from this figure, depends on returning the beam by the spacecharge'aii at the intersection of the beams. The tube illustrated inFigure 5 comprises two cathodes 3| and 32 from which emerge the beamsand 3 2. The cathodes are surrounded by electrodes 35 and 36 at anegative potential. Furthermore, the tube comprises a positive grid-likeanode 31, a positive sheet electrode 38 and an output anode 39. By thechoice of the voltages such a space charge 30 appears that the electronsof the beam 33 turn back and may return to the electrode i6.

The different electronic streams need not issue from different cathodes,since, as shown in Figure 6, thetube may be so made that the mainelectronic stream 39 is controlled by the electron' beam M and thelatter is controlled by a control grid 42. The-suction grid or aperturedauxiliary anode 43 sucks the electrons into the semiannular passagebetween the curved sheet electrodes 44 and 45, of which the electrode;44 has a positive potential and the electrode 45 a negative potential,so that the electrons may gain access along curved paths-through a.positive grid'electrode or auxiliary apertured anode 46 to the path ofthe electronic stream 60, and cause deflection, in whichjcase theelectronic stream- 40 may reach one of the main or output anodes 41 or48, or by concentration variation, as in Figure 3. The two beams issuefrom a cathode 49, from which beam 40 is obtained by a system consistingof a negative electrode 50, a positive electrode 5|, the ap- 5 erturedelectrode 46, and the sheet auxiliary anode orpositive electrode 52.

We claim:

1. An electron discharge amplifier comprising a first cathode, firstanode, means for forming the discharge from said cathode to said anodeinto an electron beam, a second cathode, means for forming the dischargefrom said second oathode into a second beam intersecting the first beam,a grid-like electrode between said second cathode and the intersectionof said beams, a third cathode, a final output anode, means for formingthe discharge from said third cathode to said final anode into a thirdbeam along a path near said first anode and transverse to the path ofsaid first beam.

2. An electron discharge device comprising a pair of output anodesmounted side by side, means comprising a main cathode for producing aconcentrated main electron beam to said output anodes, an auxiliarycathode, an auxiliary sheet anode member on the side of the path of saidmain beam opposite said auxiliary cathode, means for producing a secondconcentrated electron beam from said auxiliary cathode to said sheetmember directed across the path of said main electron beam and parallelto the plane of said main output anodes, and a grid-like anode memberextending across the path of said second electron beam between saidauxiliary cathode and the intersection of said electron beams forproducing at the intersection of said beams and between said auxiliaryanode members a space charge sufiicient to deflect said main beam fromone of said output anodes toward the other.

3. An electron discharge device comprising an output anode, a maincathode, means for concentrating' the discharge from said main cathodeto said output anode into a main beam, an auxiliary cathode, anauxiliary anode comprising two spaced members on opposite sides of thepath of said main beam, one of said members being apertured andpositioned between said auxiliary cathode and the path of said mainbeam, and means for concentrating the electron discharge 50 from saidauxiliary cathode through said apertured member of said auxiliary anodeinto a beam which intersects said main beam to produce between saidmember's and in the vicinity of the intersection of said beams a spacecharge suflicient to control said main beam.

4. An electron discharge device comprising an output anode, a maincathode, means for concentrating the discharge from said main cathodetosaid output anode into a main electron beam, an auxiliary cathode onone side of the path of said main beam, and an auxiliary anodecomprising a sheet member on the opposite side of the path of said mainbeam from said auxiliary cathode and an apertured auxiliary anode memberin registry with said sheet member and between said auxiliary cathodeand the path of said main beam, and means for forming the discharge fromsaid auxiliary cathode into an electron beam directed through saidapertured auxiliary anode to intersect saidv main. beam between saidanode members. I 1" JOHAN LODEWIJK HENDRIK JONKER. ADRIANUS J. W. M VANOVERBEEK. 7g

